18 foods to boost gut health (and reduce stress)

Jul 18

As our gut and brain are intrinsically linked, the key to better mental health and resilience lies in our diet

The importance of taking care of our gut health has been underlined by a whole raft of studies in the last few years. And what’s becoming clear is that the relationship between our gut and brain has huge implications for our mental and emotional health.

In fact, according to a new study, healthy bacteria in the gut could be the key to tackling stress, and our resilience is shaped by our gut activity.

In the study, participants with high resiliency had lower inflammation and a stronger gut barrier than those who were less resilient. A strong gut barrier is vital both for the absorption of nutrients and for blocking toxins.

The brain and the gut are connected by the body’s longest nerve, the vagus nerve.

“The vagus nerve is a key component of the wider gut-brain axis, and what’s going on in your brain can influence what’s going on in your gut and vice versa,” says Dr Megan Rossi, a gut health scientist, dietitian and research fellow at King’s College London.

“Disruption along this gut-brain axis has been associated with disorders including stress, depression, anxiety and more, with chronic stress and trauma having been linked with conditions like Irritable Bowel Syndrome,” she says.

Many of us notice the first physical effects of stress in our gut.

“We refer to ‘butterflies in my tummy’ or having an upset stomach when we’re nervous, but few of us think about the impact of our gut on our brain. In fact, it affects our perception of the world, our mental regulation and cognitive abilities, and there are strains of bacteria in our gut health that are associated with a whole range of mental health conditions,” says Lara Hughes, a clinical nutritionist and naturopathic practitioner with a background in neuroscience.

How healthy is your gut?

Gut health can be tested via stool analysis at a private clinic. “But unfortunately there is currently no single comprehensive tool that can be used to measure gut health and determine what a healthy gut is,” says Dr Rossi. Her team at King’s College London have developed this research-backed Gut Health Quiz which gives you a good idea of how your gut is.

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You may well be familiar with some of the symptoms of an unhealthy gut, such as bloating, digestive discomfort, reflux, constipation and diarrhoea. “Furthermore, when your digestive system is out of balance, you may experience brain fog and low mood,” says Hughes.

Another sign of digestive imbalance is food intolerance. “When we’re stressed, our iron depletes. This tends to cause food reactions, with people developing what they think is a food intolerance but potentially their stress is exposing the gut membrane to pathogens and bacteria,” says Hughes.

When the membrane gets compromised like this – when you have a “leaky gut” – autoimmune conditions can be triggered, making the body attack itself. “This can also cause chronic fatigue and arthritic conditions,” says Hughes.

Apart from diet, the factors that can impact the health of the gut include medicines – antibiotics, for example, not only kill the ‘bad’ bacteria but they can kill off the “good” ones too, and other prescription drugs can also impact our microbes. And it’s thought that drinking alcohol can lead to a leaky gut. There’s also growing evidence to suggest that the gut and sleep are connected through the gut-brain axis. “Just two nights of limited sleep has been shown to negatively impact our gut microbes in a way that is linked with increasing inflammation and stress hormones,” says Dr Rossi.

Why are the gut and the brain so intrinsically linked?

The gut is connected to the brain via the enteric nervous system, which includes the vagus nerve. This often means that what’s going on in your brain can influence what’s going on in your gut and vice versa. According to a study in 2020, through communication with the vagus nerve and neurotransmitter release, the gut microbiota may play a role in stress responding and may also contribute to depressive symptoms. “The gut microbiome supports immune regulation, with around 70-80 per cent of the immune system housed in the gut. During periods of stress, your gut bacteria can activate the immune system to release inflammatory markers. This low-grade inflammation is thought to contribute to many chronic conditions, including poor mental health,” says Dr Rossi. Lower inflammation and a stronger gut barrier make you more resilient.

If you’ve got bad gut health, it can impact how you perceive the world. “Good gut health makes us less likely to suffer from anxiety and depression and we experience positive emotions and good cognitive functions,” says Hughes. “Furthermore, some good bacteria help with the absorption of nutrients like magnesium and B Vitamins which are crucial for cognitive and mental health”.

How to improve your gut health and beat stress

The best foods

A healthy microbiome is driven by rich microdiversity. “It’s not just about having more “good” than “bad” bacteria – diversity of strains is key, and our microbiome is hugely impacted by the foods we eat, namely those containing prebiotics and probiotics, which helps maintain equilibrium and micro-diversity,” says Hughes.

Prebiotics are non-digestible, fibrous foods which fuel our existing beneficial microflora – since your body can’t digest them, they pass through to the lower digestive tract and are utilised as food by good bacteria, supporting the growth and functioning of the microbiota already residing in our gut. Most adults are only eating an average of about 20g of fibre a day. “Research suggests we should be consuming 30-40g fibrous foods daily to promote sufficient ingestion of prebiotics,” says Hughes. These foods include:

Wholegrains
Legumes
Garlic
Onions
Jerusalem artichoke
Leeks
Shitake mushrooms
Asparagus
Oats
Apples
Bananas

Eating natural yoghurt or kefir is an easy way to ensure there are probiotics in your diet CREDIT: iStockphoto

Probiotics are health-promoting bacteria found mainly in fermented foods. If you’re eating varied probiotic foods, you’ll not only populate your gut with beneficial bacteria, but also promote good micro-diversity amongst strains for optimal benefit. Examples of probiotics:

Hard cheeses
Kefir
Natural yoghurt
Tempeh
Kimchi
Miso
Sauerkraut

“Aim for five to eight different fruits and veg a day and make sure you include foods that contain phenolic compounds, a type of antioxidant found in green tea, grapes and avocados, which act as both prebiotic and probiotic in the stomach,” says Hughes.

The right supplements

Supplemental probiotics can also be helpful, especially for an added boost during and after periods of illness. “Look not only for the number of live bacteria (billions of Colony Forming Units / CFUs – 10-billion CFUs minimum), but also for the diversity of strains (5 strains plus ideally). Garden of Life’s Mood Plus blend is specifically formulated to support the gut-brain axis. If you think you might be deficient in iron, take a test. A gentle iron supplement can help reduce the impact of stress on the gut microbiota by increasing the absorption of iron.

Exercise and lifestyle

Exercise will not just release endorphins, the feelgood hormones for mental health, but it also massages the gut and the vagus nerve and helps get things moving through your digestive system – even a good walk will make a difference.

“Mindful movement practices like yoga have been shown to improve overall digestive health. A 2022 study suggests that yoga is an effective tool for managing irritable bowel syndrome symptoms by reducing stress through the gut-brain axis and regulating digestive movements,” says Dr Rossi.

And make sure you’re drinking plenty of water to prevent constipation which, unchecked, can lead to your body absorbing harmful toxins and pathogens.

Wade Brimage